Variable condenser



I 1,620,244 March 1927' F. E. SWOPE, JR

VARIABLE CONDENSER Filed May 18, 1923 ATTORNE.

. thereof with a saving Patented Mar. 8, 1927.

UNITED STATES PATENT OFFICE.

VARIABLE oon'nnivsnn.

Application filed May 18,

My invention relates to an improvement in variable condensers, forexample, such as are used in connection with radio receiving apparatus.I

I The object of my invention is to provide novel means for securing thefixed and movable plates of a variable condenser in order to insurecorrect alignment of the plates, reduce the parts, and enable theassembly of time and labor.

' A further object o my invention is to pro vide a variable condenser,that is, one having fixed plates ,and relatively movable plates wherebythe capadity may be varied,

which twill be of 'novelj construction and proof against warping withresultant short circuitingdue to misalignment of. the fixed andrelatively movable lates. y

Further ob ects of my invention are to proi duce a variable condenserwhich may be readily attached to-the ordinary panel and which will bevrelatively inexpensive to construct and at the same time be durable andI eflicient in use. Having now indicated in a general. way thenature,purpose and advantage of my invention, I will proceed to adetaileddescription of a preferred embodiment thereof with reference to theaccompanying drawings, in which- Y Fig. -1 is a sectional view of avariable con denser embodying my invention.

Fi 2 is a face new of a fragment of a pane showing the application ofthe condenser. I

Fig. 3 is a sectional view on line 3-3 Fig. 1.

Fig. 4 is Fig. 1.

Fig. 5 is a view of a condenser plate. Fig. 6 is a view of a platesupporting rod.

a, a represent heads or end plates of insulating material between whichthe fixed and relatively movable plates of the condenser are carried.The fixed plates 0 are slottedas at z and a sectional view on line 44are entered in slots or grooves 3 in rods (1, d.-

The rods are then squeezed longitudinally to close the slots 3 andsecure the plates. The plates when secured'on' the rods 01, d'oare s dequidistant by the lands e-between the grooves 3 in the rods. The fixedplates are held against the head a by means of nuts f, and the rodsd, dcarrying the plates 0 0' isthreaded on the end of shaft 1923. Serial No.689,731.

are secured to the heads a, a by means of nuts. A rod 9 carrying aspacer h is secured to the heads a, a.

The relatively movable plates 11 of the condenser are carried on arotatable shaft 1', be-

ing slotted, as are plates 0, for entry into slots or grooves similar togrooves 3 in rods d, d 1n the shaft 7'. The plates are secured to theshaft by squeezing it longitudinally A and when secured are spaced, bythe lands k,

spring m secured to head. a, embracing shaft 7' and bearing on a headnon shaft 7'. The spring mpresses shaft 7' against its hearing on heada, without exerting any pressure on head'a, which would tend to separatethe heads and throw the movable and fixed plates out of line. The springalso acts as a brake on the. shaft 7' so that a fine adjustment may bemade. The spring further may be used as an electrical contact, ifdesired.

The condenser is secured tothe panel 0 by means of an externallythreaded bushing 7) provided with an enlarged head g. bushing passesthrough the panel and is threaded within the .hub Z, until-the head 9bears against the panel. An indicator hand i i-is is a turning knob s.

Suitable leads 71 and ingIup the condenser.

aving now fully described my inveng serve for connect D The movable Thetion, what I claim and desire to protect by Letters Patent is:

1. A variable condenser comprising .oppositely disposed heads. a solidrod rovi'ded with a circumferential slot exten ing within the slot insaid rod, the material formingthe rod being expanded long1tud1- betweenthe heads and a condenser plate having a laterally opening slot engagednally adjacent opposlte sides of the plate 'to secure the plate in theslot.

2. A variable condenser comprising oppositely disposed heads, a solidrod provided with spaced circumferential slots extending between theheads, a plurality of condenser plates having laterally opening slotsengaged within the slots in the rod, the maagainst the'plates and securethe plates therein.

4. A variable condenser comprising. oppositely disposed heads ofinsulating material, a plurality of fixed plates mounted'between saidheads, amovable plate adapted to be moved between said fixed plates, anda spring secured to one of said heads and acting on said movable platesin a direction away from the opposite head, whereby said movable platesare positioned between said heads.- g I 5. A variable condensercomprising oppositely disposed heads of insulating material,

a plurality of fixed plates mounted between said heads,a. rotatableshaft a "plate mounted on said shaft, an end bearing for said shaftsupported by one'of said heads, and

a spring adapted to actto hold said shaft in said end bearing, saidspring being secured to and acting in a direction toward the headsupporting said bearing. I 6. A variable condenser comprising oppositelydisposed heads of insulating material, a plurality offixed platesmountedbetween said heads, a bushing in one of said'heads,

v a pin in the other head, a rotatable shaft passing through saidbushing and provided with an end bearing for said pin, a plate mountedon said shaft, and a'spring secured to said lastmentioned head andembracing said shaft, said spring acting in a direction 4 toward saidlast mentioned head to hold said shaft againstsaid pin.

7. A variable condenser comprising oppositely disposed heads ofinsulating material, a plurality of fixed plates mounted between saidheads, a bushing inone of saidheads, a pin in the other head, arotatable shaft passing through said bushing and provided with an endbearing for said pin, a plate mounted on said shaft, a flange adjacentthe end of said shaft, and a spring secured at one end ,to said lastmentioned head, the

free end of said spring embracing said shaft and bearing against saidflange, said spring acting in adirection toward said last mentioned headwhereby said shaft is held against said pin and resistance to therotation of the shaft is provided. 8. A variable condenser comprisingoppositely disposed heads of insulating material, a plurality of fixedplates mounted between, said heads, a bushing, having an internallythreaded portion, mounted in one of said heads, a panel, a bushing,having an internally threaded portion, adapted to thread into 'saidfirst mentioned bushing, mounted in said panel, a rotatable shaftadapted to pass through. said bushings and extend between said heads, aplate mounted von said shaft, a pin supported by the other head andadapted to support the end of the shaft, a

spring secured to said last mentioned head and adapted to act on saidshaft in a direction toward said last mentioned head to hold the, end ofsaid shaft against said pin, and a knob on the end of said shaftadjacent said panel whereby said shaft may be rotated manually.

In testimony of which invention, I have hereunto set my hand, atPhiladelphia, Pa, on this 12th day ofiApril, 1923.

I rnanniarcir' E. sworn, an; I

